High-efficiency end-fire 3D optical phased array based on multi-layer platform

Abstract

Beam steering device such as optical phased array (OPA) is a key component in applications of solid-state LIDAR and wireless communication. The traditional single-layer OPA results in a significant energy loss due to the substrate leakage caused by the downward coupling from the grating coupler structure. In the present disclosure, we have investigated a structure based on multi-layers Si 3 N 4 /SiO 2 platform that can form a 3D OPA to emit the light from the edge of the device with a high efficiency, a 2D converged out-coupling beam will be end-fired to the air. The high efficiency and wide horizontal beam steering are demonstrated numerically, the influence of vertical crosstalk, the delay length, number of waveguide layers, and the fabrication feasibility are also discussed.

What is claimed is: 
     
       1. A beam steering device comprising:
 a structure having a plurality of layers, the plurality of layers having first-material and second-material layers configured to form a 3D OPA to emit light from an edge of the structure and outputting a 2D converged out-coupling beam from the structure, the structure having an omega-shaped delay line, 
 wherein the plurality of layers of the structure comprises a quasi-periodic configuration. 
 
     
     
       2. The beam steering device according to  claim 1  wherein each of the first-material layers has a thickness of 800 nm and each of the second-material layers has a thickness of 500 nm sandwiched by the first-material layers. 
     
     
       3. The beam steering device according to  claim 2  wherein a spacing between adjacent layers of the plurality of layers is about 2 μm. 
     
     
       4. The beam steering device according to  claim 1  wherein each of the first-material layers has a thickness of about 800 nm or less. 
     
     
       5. The beam steering device according to  claim 1  wherein each of the second-material layers has a thickness of 500 nm or less disposed between the first-material layers. 
     
     
       6. The beam steering device according to  claim 1  wherein the structure comprises a butt-couple at an input end. 
     
     
       7. The beam steering device according to  claim 1  wherein the first-material is Si 3 N 4  and the second-material is SiO2. 
     
     
       8. The beam steering device according to  claim 1  wherein the first-material is Si and the second-material is SiO2. 
     
     
       9. The beam steering device according to  claim 1  wherein the first-material is Si and the second-material is Si3N4.